The purpose of rational choice is to provide a grand theoretical framework for designing human institutions. Once theoretical work had shown how markets optimally aggregated preferences, attempts were made to extend the theory from markets to politics. Attempts by Downs and Olson to describe elections and collective action produced relatively poor predictions, but impelled game theorists to generalize preference?based theories to include belief formation. A consequence of this change is that the theory is no longer purely axiomatic, but draws on insights about human behavior from other disciplines and empirical analysis of the role institutions play in determining beliefs.